Uptake of Atmospheric Tritium by Market Foods

Abstract

Uptake of tritium by market foods from tritiated water vapor in the air was investigated using cereals and beans purchased in Deep River, Canada. The concentrations of tissue free water tritium (TFWT) and organically bound tritium (OBT) ranged from 12 to 79 % and from 10 to 38 % respectively, of that estimated for atmospheric water vapor of the sampling month. The specific activity ratios of OBT to TFWT were constant for cereals, but variable for beans. The elevated OBT was shown to be the result of isotopic exchange of labile hydrogen by the fact that washing the foods with tritium free-water reduced their tritium contents to levels characteristic of their production sites. Thus, the contents of both labile hydrogen and free water are important parameters for the incorporation of tritium into foods on exposure to tritiated water vapor.